Preface

Few ideas have had as profound an effect on human thought as the theory of evolution. When Charles Darwin wrote in The Origin of Species (1859) that, contrary to traditional belief, the Earth’s organisms are not unchanging or immutable, but have, through a process he dubbed natural selection, diverged from other related species, he rather reluctantly delivered a blow that altered not only the human understanding of the natural world, but of human beings’ own place within it. To this day, Darwin’s theory continues to rankle certain sectors of the public. Indeed, some find the notion that we are subject to the same biological pressures as the lower species—that we descended from apes—profoundly troubling, since it implies that, as Mark Twain so succinctly put it, the world was not “made for man,”1 or that man himself was not a divine creation. Given these issues, it is perhaps not surprising that while it serves as the keystone of modern biology, enjoys universal acceptance within the scientific community, and manifests itself concretely in genetically modified crops and livestock, evolution remains a divisive topic which many consider still open for debate.

Since Darwin’s initial revelations, other transformative breakthroughs have occurred in the field of evolutionary biology. One such development came in 1953, when James Watson and Francis Crick discovered the double-helix structure of DNA, thereby illuminating the mechanism through which evolution takes place. Until that point, as Edward J. Larson notes in Evolution: The Remarkable History of a Scientific Theory, the gene was a black box that many scientists thought so complex as to require decades to decipher. However, Watson and Crick determined that the entire genetic code was composed of four base molecules: adenine, thymine, guanine, and cytosine, which are often represented by the initials: A, T, G, and C. “For those not studying biology at the time in the early 1950s, it is hard to imagine the impact the discovery of DNA had on our understanding of how the world works,” the famed zoologist Edward O. Wilson recalled. “If heredity can be reduced to a chain of four molecular letters—granted, billions of such letters to prescribe a whole organism—would it not also be possible to reduce and accelerate the analysis of ecosystems and complex animal behavior?” Indeed, having been provided the means to decode the “book of life,” biologists are seeking answers to such important questions as what determines an organism’s lifespan and whether early humans interbred with Neanderthals.

Given that the process of evolution and our understanding of it are both works in progress, this volume is by no means comprehensive. Rather, it seeks to highlight some of the more important discoveries and debates within the field. The first chapter provides the reader with an overview of evolutionary theory by presenting biographies of some of the more important figures in its development. For readers interested in the contemporary political debate over teaching evolutionary theory in public schools, the second chapter presents analysis from both sides. The next two sections examine two sources of evidence for various evolutionary theories—the human genome and the fossil record. Finally, the fifth chapter explores the development of higher cognition and culture in human beings and our primate relatives.

In conclusion, we would like to offer our sincere appreciation to the writers and publishers who granted permission to reprint their work. Thanks are also due to the many people who contributed to this book, particularly our H. W. Wilson Company colleagues David Ramm, Lynn Messina, Paul McCaffrey, Richard Stein, and Albert Rolls.

In-Young Chang and Jennifer Curry
August 2006